FGF4 and granular cell tumor: Of note, regarding potential reprogramming of GCT cells due to microenvironmental cues, we have previously reported that the seminoma cell line TCam‐2 differentiates under TGF‐β1, EGF, and FGF4 application for 8 days directly into a mixed non‐seminoma (no EC component) [72] or could be reprogrammed into an EC‐like cell fate after xenotransplantation into the murine flank for at least 4 weeks [73].